In the past frack or other treatment valves operated with a single sleeve that had to be moved in opposed directions to open and close the ports. In some deviated boreholes enough force to shift a sleeve in the downhole direction with set down weight is not available. Sliding sleeve valves were used in pairs or did not have the capacity to be reopened after closing or had other limitations making them unsuitable for treatment is certain applications. The following references are illustrative of some known designs of sliding sleeve valves for borehole treatment operations: U.S. Pat. Nos. 7,591,312; 8,127,847 and US 2009/0139717.
The present invention addresses the issues of the prior designs of sliding sleeve valves for treatment applications in a borehole by providing a tandem sleeve design where the sleeves are pulled uphole. The first sleeve movement opens housing ports and movement of a second sleeve in the same direction moves the second sleeve to where the first sleeve started for the closed position of the ports in the valve housing. The closing sleeve can also be functioned back down in the event the ports in the valve housing need to be reopened. The opening sleeve can be locked in the open position after it is shifted. Known spears using selectively supported collets can be used to shift the opening sleeve and a linkage type shifting tool such as an HB-3 shifting tool from Baker Hughes Incorporated can be used to shift the closing sleeve to close the housing ports. Two HB-3 shifters oriented in mirror image can be used to move the closing sleeve up for closing the housing ports with one shifter and to move the closing sleeve back down to reopen the housing ports.
Those skilled in the art will have a better understanding of the present invention from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined from the appended claims.